Spinopelvic sagittal balance: what does the radiologist need to know?

In the anatomy of a normal spine, due to the curvatures in various regions, the C7 plumb line (C7PL) passes through the sacrum so that the head is centered over the pelvic-ball and socket hip and ankle joints. A failure to recognize malalignment in the sagittal plane can affect the patient's activity as well as social interaction due to deficient forward gaze. The sagittal balance configuration leads to the body undertaking the least muscular activities as possible necessary to maintain spinal balance. Global sagittal imbalance is energy consuming and often results in painful compensatory mechanisms that in turn negatively influence the patient's quality of life, self-image, and social interaction due to inability to maintain a horizontal gaze. Deformity, scoliosis, kyphosis, trauma, and/or surgery are some ways that this optimal configuration can be disturbed, thus requiring higher muscular activity to maintain posture and balance. Several parameters such as the thoracic kyphosis (TK), lumbar lordosis (LL), pelvic incidence (PI), sacral slope (SS), and hip and leg positions influence the sagittal balance and thus the optimal configuration of spinal alignment. This review examines the clinical and biomechanical aspects of spinal imbalance, and the biomechanics of spinal balance as dictated by deformities—ankylosing spondylitis (AS), scoliosis and kyphosis; surgical corrections—pedicle subtraction osteotomies (PSO), long segment stabilizations, and consequent postural complications like proximal and distal junctional kyphosis. The study of the biomechanics involved in spinal imbalance is relatively new and thus the literature is rather sparse. This review suggests several potential research topics in the area of spinal biomechanics.

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Implications of Spinopelvic Alignment for the Spine Surgeon

Neurosurgery ◽

10.1227/neu.0b013e31823262ea ◽

2011 ◽

Vol 70 (3) ◽

pp. 707-721 ◽

Cited By ~ 55

Author(s):

Vivek A. Mehta ◽

Anubhav Amin ◽

Ibrahim Omeis ◽

Ziya L. Gokaslan ◽

Oren N. Gottfried

Keyword(s):

Sagittal Balance ◽

Lumbar Lordosis ◽

Pelvic Incidence ◽

Degenerative Spondylolisthesis ◽

Disease Process ◽

Sacral Slope ◽

Sagittal Imbalance ◽

Spinopelvic Parameters ◽

Spinopelvic Alignment ◽

Spinopelvic Balance

Abstract The relation of the pelvis to the spine has previously been overlooked as a contributor to sagittal balance. However, it is now recognized that spinopelvic alignment is important to maintain an energy-efficient posture in normal and disease states. The pelvis is characterized by an important anatomic landmark, the pelvic incidence (PI). The PI does not change after adolescence, and it directly influences pelvic alignment, including the parameters of pelvic tilt (PT) and sacral slope (SS) (PI = PT 1 SS), overall sagittal spinal balance, and lumbar lordosis. In the setting of an elevated PI, the spineadapts with increased lumbar lordosis. To prevent or limit sagittal imbalance, the spine may also compensate with increased PT or pelvic retroversion to attempt to maintain anupright posture. Abnormal spinopelvic parameters contribute to multiple spinal conditions including isthmic spondylolysis, degenerative spondylolisthesis, deformity, and impact outcome after spinal fusion. Sagittal balance, pelvic incidence, and all spinopelvic parameters are easily and reliably measured on standing, full-spine (lateral) radiographs, and it is essential to accurately assess and measure these sagittal values to understand their potential role in the disease process, and to promote spinopelvic balance at surgery. In this article, we provide a comprehensive review of the literature regarding the implications of abnormal spinopelvic parameters and discuss surgical strategies for correction of sagittal balance. Additionally, the authors rate and critique the quality of the literature cited in a systematic review approach to give the reader an estimate of the veracity of the conclusions reached from these reports.

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Implications of Spinopelvic Alignment for the Spine Surgeon

Neurosurgery ◽

10.1227/01.neu.0000462077.50830.1a ◽

2011 ◽

Vol 76 (suppl_1) ◽

pp. S42-S56 ◽

Cited By ~ 29

Author(s):

Vivek A. Mehta ◽

Anubhav Amin ◽

Ibrahim Omeis ◽

Ziya L. Gokaslan ◽

Oren N. Gottfried

Keyword(s):

Sagittal Balance ◽

Lumbar Lordosis ◽

Pelvic Incidence ◽

Degenerative Spondylolisthesis ◽

Disease Process ◽

Sacral Slope ◽

Sagittal Imbalance ◽

Spinopelvic Parameters ◽

Spinopelvic Alignment ◽

Spinopelvic Balance

Abstract The relation of the pelvis to the spine has previously been overlooked as a contributor to sagittal balance. However, it is now recognized that spinopelvic alignment is important to maintain an energy-efficient posture in normal and disease states. The pelvis is characterized by an important anatomic landmark, the pelvic incidence (PI). The PI does not change after adolescence, and it directly influences pelvic alignment, including the parameters of pelvic tilt (PT) and sacral slope (SS) (PI = PT 1 SS), overall sagittal spinal balance, and lumbar lordosis. In the setting of an elevated PI, the spineadapts with increased lumbar lordosis. To prevent or limit sagittal imbalance, the spine may also compensate with increased PT or pelvic retroversion to attempt to maintain anupright posture. Abnormal spinopelvic parameters contribute to multiple spinal conditions including isthmic spondylolysis, degenerative spondylolisthesis, deformity, and impact outcome after spinal fusion. Sagittal balance, pelvic incidence, and all spinopelvic parameters are easily and reliably measured on standing, full-spine (lateral) radiographs, and it is essential to accurately assess and measure these sagittal values to understand their potential role in the disease process, and to promote spinopelvic balance at surgery. In this article, we provide a comprehensive review of the literature regarding the implications of abnormal spinopelvic parameters and discuss surgical strategies for correction of sagittal balance. Additionally, the authors rate and critique the quality of the literature cited in a systematic review approach to give the reader an estimate of the veracity of the conclusions reached from these reports.

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Clinical and radiological aspects of the sagittal balance of the spine in children with achondroplasia

Pediatric Traumatology Orthopaedics and Reconstructive Surgery ◽

10.17816/ptors646-12 ◽

2018 ◽

Vol 6 (4) ◽

pp. 6-12

Author(s):

Oksana G. Prudnikova ◽

Anna M. Aranovich

Keyword(s):

Sagittal Balance ◽

Lumbar Lordosis ◽

Clinical Manifestations ◽

Pain Syndrome ◽

Lower Limbs ◽

Sagittal Imbalance ◽

Compensatory Mechanisms ◽

Lateral Instability ◽

Hip Joints ◽

Cross Sectional

Background. Changes in the spine with achondroplasia are represented by disorders of synostosis, the presence of wedge-shaped vertebrae, underdevelopment of the sacrum, changes in the size of the roots of the arches, stenosis of the spinal canal, and changes in the sagittal balance. Aim. To investigate the clinical and radiological features of the sagittal balance of the spine in children with achondroplasia. Materials and methods. We performed a cross-sectional clinical and radiological study of 16 patients with achondroplasia aged 6–17 years (mean, 9.2 ± 3.3 years). Radiographically, the parameters of the sagittal balance of the spine and pelvis and scoliosis were evaluated. Clinical evaluation included orthopedic and neurological status and back pain syndrome. Results. The anatomic features of patients with achondroplasia are limb shortening, O-shaped curvature of the lower extremities with lateral instability of the knee joints, and flexural contractures of the hip joints. With restriction of mobility in the hip joints, compensatory mechanisms for correcting sagittal imbalance are triggered: pelvic incline, lumbar lordosis, and thoracic kyphosis change. The clinical manifestations of sagittal imbalance in enrolled children were hypokyphosis of the thoracic spine in 100% and an increase in lumbar lordosis in 56.25% of patients. In 50% of patients, wedge-shaped deformation of vertebral bodies was diagnosed at the level of the thoracolumbar transition with the formation of local kyphosis. Neurological disorders have not been diagnosed in children. Conclusions. The anatomical features of the lower limbs and hip joints in achondroplasia reflect the biomechanical features of the relationship between the spine, pelvis, and lower limbs, which should be considered when planning for orthopedic and spinal surgery after prediction.

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Outcomes of Surgical Treatment of High-Grade Spondylolisthesis (Monocenter Cohort and Literature Review)

Traumatology and Orthopedics of Russia ◽

10.21823/2311-2905-2019-25-3-100-111 ◽

2019 ◽

Vol 25 (3) ◽

pp. 100-111

Author(s):

S. O. Ryabykh ◽

D. M. Savin ◽

E. Yu. Filatov ◽

A. O. Kotelnikov ◽

M. S. Sayfutdinov

Keyword(s):

Surgical Treatment ◽

Sagittal Balance ◽

Life Quality ◽

Pain Syndrome ◽

Lower Limbs ◽

Sagittal Imbalance ◽

High Grade ◽

X Rays ◽

Level Of Evidence ◽

Severity Grade

Purpose — to evaluate outcomes of surgical treatment for high-grade spondylolisthesis using bone-disc-bone osteotomy, reduction and fixation through the dorsal approach. Materials and Methods. The authors retrospectively examined a monocenter five-year cohort (IV level of evidence). The study included 10 patients aging from 7 to 22 years (Me — 12 years, M±m — 13.1±4.1 years) who underwent surgery due to high-grade spondylolysis antelisthesis in the period from 2012 to 2017. Displacement was located in L5-S1 segments and corresponded to types 4-6 by AO Spine SDSG classification in all patients. Catamnesis was followed for the period from 1 to 5 years. Surgical procedures included bone-disc-bone osteotomy, L5 reduction and dorsal instrumental multi-bearing (from 2 to 5 spinal motion segments) using reduction transpedicular screws. The following parameters were evaluated: pain syndrome prior and after surgery, sagittal balance, spondylolisthesis mobility on the functional x-rays or CYs, severity grade of anterior spondylolysis, criteria of spontaneous muscular activity and MEPs as well as structure of postoperative complications. Results. L5 displacement prior to surgery was 92.6±25.2%, after surgery — 25.4±16.6% (Z = -2.805, p = 0.005). Patients with sagittal imbalance demonstrated normalization after the surgery allowing to re-classify pathology as “balanced spondylolisthesis”: PI from 67.9±8.6 to 67.5±8.7 (Z = 0,000, p = 1,000), PT from 26.8±13.3 to 20.1±7.1 (Z = -2,090, p = 0.037), SS from 41.3±8.7 to 47.3±9.7 (Z = -1.886, p = 0.059), SA from 34.9±36.3° to 8.6±7.1° (Z = -2.803, p = 0.005). 3 cases of transient L5 radiculopathy with full regress after conservative 6 months’ treatment were reported in the early follow up period (on day 3 after procedure). Pain syndrome dynamics on VAS scale prior to and after the surgery were as follows: spine 8.1±1.0 and 0.5±0.5 (Z = -2.814, p = 0.005), lower limbs 6.8±1.5 and 0.4±0.7 (Z = -2.812, p = 0.005), respectively. Life quality indices by SRS-24 score prior to and after the surgery were 62.6±7.9 and 90.7±12.4 (Z = -2.803, p = 0.005). Mobility of spondylolisthesis was observed in 9 patients. Spondylolisthesis severity by Bridwell classification in late period scored from 1 to 3 points. Conclusion. Use of AO Spine SDSG classification along with assessment of sagittal balance as well as severity of neurological deficit and pain syndrome allow to define the severity grade of spondylolisthesis, while normalization of parameters after the surgery speaks for positive treatment outcome. Extensive release during bone-disc-bone osteotomy at L5-S1 level along with altering tilt angle of the sacrum is the key factor for mobilization and radical correction of pelvic balance in high-grade spondylolisthesis. Outcomes of surgical treatment in the analyzed cohort demonstrate significant improvement in life quality (by SRS-24 score) and reduced pain syndrome (by VAS) in patients. At the same time precise compliance to the procedure protocol and intraoperative neuro-monitoring of MEPs allow to decrease risk of complications.

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Increasing pelvic incidence is associated with more global sagittal imbalance in ankylosing spondylitis with thoracolumbar kyphosis

10.21203/rs.2.16543/v2 ◽

2019 ◽

Author(s):

Diyu Song ◽

Guoquan Zheng ◽

Tianhao Wang ◽

Dengbin Qi ◽

Yan Wang

Keyword(s):

Ankylosing Spondylitis ◽

Sagittal Balance ◽

Pelvic Incidence ◽

Pearson Correlation ◽

Control Group ◽

Sacral Slope ◽

Sagittal Imbalance ◽

Thoracolumbar Kyphosis ◽

Spinopelvic Parameters ◽

The Relationship

Abstract Background: Ankylosing spondylitis (AS) patients with kyphosis have an abnormal spinopelvic alignment and pelvic morphology. Most studies focus on the relationship of pelvic tilt (PT) or sacral slope (SS) and deformity, and relatively few studies have addressed the relationship between pelvic incidence (PI) and kyphosis in AS patients. The purpose of this study is to analyze the correlation between pelvic incidence (PI) and the spinopelvic parameters describing local deformity or global sagittal balance in AS patients with thoracolumbar kyphosis. Methods: A total of 94 patients with AS (91 males and 3 females) and 30 controls were reviewed. Sagittal spinopelvic parameters, including PI, PT, SS, thoracic kyphosis (TK), thoracolumbar kyphosis (TLK), lumbar lordosis(LL), sagittal vertical axis(SVA), the first thoracic vertebra pelvic angle(TPA), spinosacral angle(SSA) and spinopelvic angle(SPA) were measured. Pearson correlation (r) and unary linear regression model were used to analysis the relationship between PI and other spinopelvic parameters. Results: Compared with the control group, the AS patients had significantly higher PI(47.4˚ vs. 43.2˚, P<0.001). PI in AS patients was found to be significantly positively correlated with TPA(r=0.533, R2=0.284, P<0.001), and negatively correlated with SPA(r=-0.504, R2=0.254, P<0.001). However, no correlations were found between PI and SVA, SSA, TK, TLK or LL in AS patients. Conclusion: This study revealed that increasing PI was significantly correlated with more global sagittal imbalance, not with the local deformity in AS patients with thoracolumbar kyphosis. Key Words: ankylosing spondylitis, pelvic incidence, sagittal spinopelvic parameters, global sagittal balance

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Sacral pedicle subtraction osteotomy for an extreme case of positive sagittal balance: case report

Journal of Neurosurgery Spine ◽

10.3171/2017.8.spine17550 ◽

2018 ◽

Vol 28 (5) ◽

pp. 532-535 ◽

Cited By ~ 5

Author(s):

Ali K. Ozturk ◽

Patricia Zadnik Sullivan ◽

Vincent Arlet

Keyword(s):

Case Report ◽

Sagittal Balance ◽

Vertebral Column ◽

Extreme Case ◽

Pedicle Subtraction Osteotomy ◽

Sagittal Imbalance ◽

Review Of The Literature ◽

Spinal Balance ◽

Balance Case ◽

Sagittal Spinal Balance

The importance of sagittal spinal balance and lumbopelvic parameters is now well understood. The popularization of various osteotomies, including Smith-Peterson, Ponte, and pedicle subtraction osteotomies (PSOs), as well as vertebral column resections, have greatly enhanced the spine surgeon’s ability to recognize and effectively treat sagittal imbalance. Yet rare circumstances remain, most notably in distal kyphotic deformities and patients with extremely elevated pelvic incidences, where these techniques remain inadequate. In this article, the authors describe a patient with severe sagittal imbalance despite multiple prior anterior and posterior reconstructive surgeries in which a sacral PSO was performed with good results. A description of this technique as well as a brief review of the literature is provided.

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Correction of Posture Deviations in the Sagittal Plane Using the Pilates Method

SPORT AND SOCIETY ◽

10.36836/uaic/fefs/10.50 ◽

2019 ◽

pp. 3-13

Author(s):

Alexandru Cîtea ◽

George-Sebastian Iacob

Keyword(s):

Low Back Pain ◽

Back Pain ◽

Postural Control ◽

Human Body ◽

Sagittal Plane ◽

The Body ◽

Lower Limbs ◽

Low Back ◽

Pilates Method ◽

The Relationship

Posture is commonly perceived as the relationship between the segments of the human body upright. Certain parts of the body such as the cephalic extremity, neck, torso, upper and lower limbs are involved in the final posture of the body. Musculoskeletal instabilities and reduced postural control lead to the installation of nonstructural posture deviations in all 3 anatomical planes. When we talk about the sagittal plane, it was concluded that there are 4 main types of posture deviation: hyperlordotic posture, kyphotic posture, rectitude and "sway-back" posture.Pilates method has become in the last decade a much more popular formof exercise used in rehabilitation. The Pilates method is frequently prescribed to people with low back pain due to their orientation on the stabilizing muscles of the pelvis. Pilates exercise is thus theorized to help reactivate the muscles and, by doingso, increases lumbar support, reduces pain, and improves body alignment.

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Sagittal Deformity Correction in a Patient Suffering From Diffuse Idiopathic Skeletal Hyperostosis Who Previously Underwent a Total Hip and Bilateral Knee Replacement

Geriatric Orthopaedic Surgery & Rehabilitation ◽

10.1177/2151459321992745 ◽

2021 ◽

Vol 12 ◽

pp. 215145932199274

Author(s):

Victor Garcia-Martin ◽

Ana Verdejo-González ◽

David Ruiz-Picazo ◽

José Ramírez-Villaescusa

Keyword(s):

Knee Replacement ◽

Spinal Deformity ◽

Diffuse Idiopathic Skeletal Hyperostosis ◽

Deformity Correction ◽

Pedicle Subtraction Osteotomy ◽

Lower Limbs ◽

Sagittal Imbalance ◽

Total Hip ◽

Correction Technique ◽

Compensation Mechanisms

Introduction: Physiological aging frequently leads to degenerative changes and spinal deformity. In patients with hypolordotic fusions or ankylosing illnesses such as diffuse idiopathic skeletal hyperostosis or ankylosing spondylitis, compensation mechanisms can be altered causing severe pain and disability. In addition, if a total hip replacement and/or knee replacement is performed, both pelvic and lower limbs compensation mechanisms could be damaged and prosthetic dislocation or impingement syndrome could be present. Pedicle subtraction osteotomy has proven to be the optimal correction technique for spinal deformation in patients suffering from a rigid spine. Case Presentation: A 70-year-old male patient with diffuse idiopathic skeletal hyperostosis criteria and a rigid lumbar kyphosis, who previously underwent a total hip and knee replacement, had severe disability. We then performed corrective surgery by doing a pedicle subtraction osteotomy. The procedure and outcomes are presented here. Conclusion: In symptomatic patients with sagittal imbalance and a rigid spine, pedicle subtraction osteotomy can indeed correct spinal deformity and re-establish sagittal balance.

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Assessment of Normal Sagittal Alignment of the Spine and Pelvis in Children and Adolescents

BioMed Research International ◽

10.1155/2013/842624 ◽

2013 ◽

Vol 2013 ◽

pp. 1-7 ◽

Cited By ~ 14

Author(s):

Hasan Ghandhari ◽

Hamid Hesarikia ◽

Ebrahim Ameri ◽

Abolfazl Noori

Keyword(s):

Children And Adolescents ◽

Sagittal Balance ◽

Sagittal Alignment ◽

Demographic Data ◽

Lateral View ◽

Old People ◽

Spinopelvic Parameters ◽

Spinopelvic Balance ◽

History Of ◽

Data History

Aim. We aimed to determine spinopelvic balance in 8–19-year-old-people in order to assess pelvic and spinal parameters in sagittal view.Methods. Ninety-eight healthy students aged 8–19 years, who lived in the central parts of Tehran, were assessed. Demographic data, history of present and past diseases, height (cm), and weight (kg) were collected. Each subject was examined by an orthopedic surgeon and spinal radiographs in lateral view were obtained. Eight spinopelvic parameters were measured by 2 orthopedic spine surgeons.Results. Ninety-eight subjects, among which 48 were girls (49%) and 50 boys (51%), with a mean age of13.6±2.9years (range: 8–19) were evaluated. Mean height and weight of children were153.6±15.6cm and49.9±13.1kgs, respectively. Mean TK, LL, TT, LT, and PI of subjects were 37.1 ± 9.9°, 39.6 ± 12.4°, 7.08 ± 4.9°, 12.0 ± 5.9°, and 45.37 ± 10.7°, respectively.Conclusion. Preoperation planning for spinal fusion surgeries via applying PI seems reasonable. Predicating “abnormal” to lordosis and kyphosis values alone without considering overall sagittal balance is incorrect. Mean of SS and TK in our population is slightly less than that in Caucasians.

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